/src/botan/src/lib/hash/comb4p/comb4p.cpp
Line | Count | Source (jump to first uncovered line) |
1 | | /* |
2 | | * Comb4P hash combiner |
3 | | * (C) 2010 Jack Lloyd |
4 | | * |
5 | | * Botan is released under the Simplified BSD License (see license.txt) |
6 | | */ |
7 | | |
8 | | #include <botan/internal/comb4p.h> |
9 | | #include <botan/exceptn.h> |
10 | | |
11 | | namespace Botan { |
12 | | |
13 | | namespace { |
14 | | |
15 | | void comb4p_round(secure_vector<uint8_t>& out, |
16 | | const secure_vector<uint8_t>& in, |
17 | | uint8_t round_no, |
18 | | HashFunction& h1, |
19 | | HashFunction& h2) |
20 | 0 | { |
21 | 0 | h1.update(round_no); |
22 | 0 | h2.update(round_no); |
23 | |
|
24 | 0 | h1.update(in.data(), in.size()); |
25 | 0 | h2.update(in.data(), in.size()); |
26 | |
|
27 | 0 | secure_vector<uint8_t> h_buf = h1.final(); |
28 | 0 | xor_buf(out.data(), h_buf.data(), std::min(out.size(), h_buf.size())); |
29 | |
|
30 | 0 | h_buf = h2.final(); |
31 | 0 | xor_buf(out.data(), h_buf.data(), std::min(out.size(), h_buf.size())); |
32 | 0 | } |
33 | | |
34 | | } |
35 | | |
36 | | Comb4P::Comb4P(std::unique_ptr<HashFunction> h1, std::unique_ptr<HashFunction> h2) : |
37 | | m_hash1(std::move(h1)), |
38 | | m_hash2(std::move(h2)) |
39 | 0 | { |
40 | 0 | if(m_hash1->name() == m_hash2->name()) |
41 | 0 | throw Invalid_Argument("Comb4P: Must use two distinct hashes"); |
42 | | |
43 | 0 | if(m_hash1->output_length() != m_hash2->output_length()) |
44 | 0 | throw Invalid_Argument("Comb4P: Incompatible hashes " + |
45 | 0 | m_hash1->name() + " and " + |
46 | 0 | m_hash2->name()); |
47 | | |
48 | 0 | clear(); |
49 | 0 | } |
50 | | |
51 | | size_t Comb4P::hash_block_size() const |
52 | 0 | { |
53 | 0 | if(m_hash1->hash_block_size() == m_hash2->hash_block_size()) |
54 | 0 | return m_hash1->hash_block_size(); |
55 | | |
56 | | /* |
57 | | * Return LCM of the block sizes? This would probably be OK for |
58 | | * HMAC, which is the main thing relying on knowing the block size. |
59 | | */ |
60 | 0 | return 0; |
61 | 0 | } |
62 | | |
63 | | void Comb4P::clear() |
64 | 0 | { |
65 | 0 | m_hash1->clear(); |
66 | 0 | m_hash2->clear(); |
67 | | |
68 | | // Prep for processing next message, if any |
69 | 0 | m_hash1->update(0); |
70 | 0 | m_hash2->update(0); |
71 | 0 | } |
72 | | |
73 | | std::unique_ptr<HashFunction> Comb4P::copy_state() const |
74 | 0 | { |
75 | | // Can't use make_unique as this constructor is private |
76 | 0 | std::unique_ptr<Comb4P> copy(new Comb4P); |
77 | 0 | copy->m_hash1 = m_hash1->copy_state(); |
78 | 0 | copy->m_hash2 = m_hash2->copy_state(); |
79 | 0 | return copy; |
80 | 0 | } |
81 | | |
82 | | void Comb4P::add_data(const uint8_t input[], size_t length) |
83 | 0 | { |
84 | 0 | m_hash1->update(input, length); |
85 | 0 | m_hash2->update(input, length); |
86 | 0 | } |
87 | | |
88 | | void Comb4P::final_result(uint8_t out[]) |
89 | 0 | { |
90 | 0 | secure_vector<uint8_t> h1 = m_hash1->final(); |
91 | 0 | secure_vector<uint8_t> h2 = m_hash2->final(); |
92 | | |
93 | | // First round |
94 | 0 | xor_buf(h1.data(), h2.data(), std::min(h1.size(), h2.size())); |
95 | | |
96 | | // Second round |
97 | 0 | comb4p_round(h2, h1, 1, *m_hash1, *m_hash2); |
98 | | |
99 | | // Third round |
100 | 0 | comb4p_round(h1, h2, 2, *m_hash1, *m_hash2); |
101 | |
|
102 | 0 | copy_mem(out , h1.data(), h1.size()); |
103 | 0 | copy_mem(out + h1.size(), h2.data(), h2.size()); |
104 | | |
105 | | // Prep for processing next message, if any |
106 | 0 | m_hash1->update(0); |
107 | 0 | m_hash2->update(0); |
108 | 0 | } |
109 | | |
110 | | } |
111 | | |